Diverting agents for well stimulation

Abstract

The present application provides expandable chemical diverting agents, such as flexible polyurethanes and swellable hydrogels, or chemical precursors thereof. Methods of using these expandable diverting agents for treating a subterranean formation are also provided. An example of subterranean formation treatment process described in the present application is wellbore stimulation, such as hydraulic fracturing or matrix acid treatment.

What is claimed is: 
     
       1. A method of treating a subterranean formation penetrated by a wellbore and comprising a flow channel protruding from an outside diameter of the wellbore into the subterranean formation, the method comprising
 introducing into the flow channel a diverting agent that is adapted to expand in response to an increase in size or volume of the flow channel thereby maintaining or increasing a contact area between the diverting agent and an inner surface of the flow channel, 
 wherein the diverting agent comprises a flexible porous polyurethane material and introducing the diverting agent into the flow channel comprises introducing into the flow channel a liquid pre-polymer blend comprising a polyisocyanate component and a polyol component which chemically react in the flow channel to produce the flexible porous polyurethane material. 
 
     
     
       2. The method of  claim 1 , wherein the treating of the subterranean formation comprises stimulation of the subterranean formation. 
     
     
       3. The method of  claim 2 , wherein the stimulation comprises hydraulic fracturing. 
     
     
       4. The method of  claim 3 , wherein the flow channel comprises a fracture. 
     
     
       5. The method of  claim 2 , wherein the stimulation comprises an acid treatment. 
     
     
       6. The method of  claim 5 , wherein the flow channel comprises a wormhole. 
     
     
       7. The method of  claim 1 , wherein the flexible porous polyurethane material comprises a polyurethane foam. 
     
     
       8. The method of  claim 1 , comprising introducing a treatment fluid into the wellbore before, after, or concurrently with introducing the diverting agent into the flowing channel. 
     
     
       9. The method of  claim 8 , wherein the treatment fluid is a stimulation fluid. 
     
     
       10. The method of  claim 1 , wherein the diverting agent is degradable. 
     
     
       11. The method of  claim 10 , wherein the diverting agent is degradable by hydrolysis, oxidation, or reduction. 
     
     
       12. The method of  claim 10 , wherein the diverting agent is degradable by light, heat, or pressure.